themselves the labours of the nest, just as they would have done in their own home. The Amazon Ant seems to be utterly incapable of work; and in one notable instance, when a number of them were confined in a glass-case, together with some pupæ, they were not only unable to rear the young, but could not even feed themselves, so that the greater number died from hunger. By way of experiment, a single specimen of the slave Ant (Formica fusca) was introduced into the case, when the state of affairs was at once altered. The tiny creature undertook the whole care of the family, fed the still living Amazon Ants, and took charge of the pupa until they were developed into perfect insects.

Some writers have enlarged upon the hard lot of the slave Ants, imagining their servitude to be as distasteful to them as it is sometimes made to human slaves. Mr. Westwood, however, points out very clearly that any compassion bestowed upon them is wasted, and that the lot of the "helots "-if they may be so called-is precisely that for which they were made. The labours which the little creatures undertake are not arbitrarily forced upon them by the dread of punishment, but are urged upon them by the instincts implanted within them. They would have worked in precisely the same manner, and with exactly the same assiduity, in their own nests as in that of their captors, and the labours are undertaken as willingly in the one case as in the other.

They find themselves perfectly at home, and are in every respect on a par with their so-called masters. In point of fact, however, the real masters in the nest are the slaves, for upon them the Amazons are dependent from their earliest days to the end of their life, and without them the entire community would perish. The slaves have no other home but that to which they have been brought, and are no more to be pitied than are dogs, cattle, and other domestic animals that never have freedom. Indeed, none but solitary animals can be free even in the wild state, for they are held in absolute servitude by the leaders of the herds, and, if they dare to disobey, are summarily punished.

As the slaves are always neuters, it is necessary that fresh importations should be made as fast as the demand for workers exceeds the supply; and it is really a wonderful thing that the

Amazon Ants should always select the pupa which will afterwards be developed into neuters, and never take those from which males or females will issue.

The Amazon of the Continent is not the only Ant which enslaves the neuters of another species, for in different parts of the world several species of Ants have been observed which seize upon workers belonging to other nests, and bring them to do the work of the home. A Brazilian species (Myrmica paleata) has been observed to act in this manner.

IN the accompanying illustration are shown two remarkable nests, made by insects of the same genus, which have been placed side by side in order to show the different manner in which cells are arranged by insects which are closely allied to each other.

The smaller, though more conspicuous nest, is formed by an insect which is called Polistes aterrima, a name which is very appropriate to the creature, inasmuch as the generic title signifies a builder, or the founder of a city, and the specific name signifies intense blackness, and is given to the insect on account

of its colour. In general shape the insect resembles other species of its genus, but is rather larger than the generality of its kin, and is conspicuous for its deep black colour.

The method of nidification which this species adopts is very peculiar. The cells are formed with beautiful regularity, but are arranged in a very curious fashion. They are placed with their mouths downwards, as is frequently the custom with the cells of hymenoptera, but are not quite perpendicular, inclining alternately to either side. Each cell is set rather lower than its predecessor, so that the general effect is very peculiar, and gives to the cell-group a character which renders it at once recognisable.

THE second nest which is represented in the same illustration is scarcely so striking in appearance as the preceding, but is equally interesting, and to many minds more so, because the architect is at present unknown, and there is some little mystery about the edifice. That it is the work of a Polistes is evident enough from the character of the cells, but it is not made by any of the numerous species whose nests are already in European collections.

The colour of the combs is a rather sombre brown, so that at a little distance the whole group would easily escape notice, especially if it were buried in the depths of the forest, as is the case with many similar nests. The cells are about the same size as those of the curious clay nest which has already been described, but they are undefended by any covering, and exposed to the weather.

It has been suggested by some observers that the combs might have been originally protected by an outer case, and that the case itself has been lost. The formation of the branch, however, from which the combs are hung, serves to militate against any such theory, as the twigs project so far that they must have been enveloped by the covering if it ever existed, while upon them there is no trace of any such material as that of which the nest is made. The inference is, therefore, that they were never intended to be protected by a cover, but that they were intentionally exposed to the air, as is the case with the habitations of Polistes and several allied insects, whose homes will shortly be described.

One of the most curious points in the construction of this nest is the manner in which it is suspended to the branch. As is shown in the illustration, the combs are comparatively narrow at the point of attachment, and gradually increase in width, so that their weight, when filled with the young brood, must be considerable, and the strain on the upper part of the comb very great. The manner in which the insect has met this difficulty is really wonderful. It has not made the upper part of the comb to consist of a solid mass, as is the case with the clay nest which has just been described, but has utilized almost every portion of the comb from the top to the bottom. But, in order to obtain the needful strength, the upper part is constructed after a manner that is widely different from that which prevails upon the lower and wider portion of the comb.

If one of the combs were broken across, the lower half would much resemble, except in colour, the nest of an ordinary wasp, except that the cells are smaller, and the material stronger. But, towards the top, the partitions between the cells become thicker, and in consequence the cells are fewer. This increased strength is chiefly found in the partitions which run perpendicularly, and which are so thick, that the hexagonal form of the cells becomes obscured, the great object being, not the exact shape of the cells, but their ability to bear the weight of the comb below.

The general effect of this modification can be easily imitated by taking an oblong piece of linen, rounding the corners, and plaiting one end, just as ladies gather in the upper part of an apron. The longitudinal folds will then represent the perpendicular partitions of the cells, and will show how strength is gained without needless expenditure of material. The strengthened partitions do not run quite perpendicularly, but are slightly irregular, just as would be the case with the folds of the linen if it were fastened to a branch by the plaited end, and suffered to hang loosely.

THE history of Social Insects would be incomplete without the mention of several British insects, which are plentiful enough, but which are scarcely known as well as they deserve. These are the creatures which are popularly known as CARDER BEES, because they prepare the materials for their nest in a manner

similar to that which is employed in carding cotton wool or heckling flax.

belonging to that

Several species of Carder Bee are known, all familiar group of insects called Humble Bees. Among these, as among Humble Bees in general, there is a great variety of colour, so that the same species has been called by different names, even by skilled entomologists. For example, in Kirby's admirable monograph of British Bees, no less than seven varieties of the commonest species of Carder Bee (Bombus muscorum) are given as separate species.

That such mistakes should be made is no matter of surprise when we take into consideration the capriciousness with which the colours of this species are distributed among its members. Among the queen Bees, the abdomen is sometimes marked with rings of yellow, black and red, and is sometimes red at the base and tip and black in the middle. The worker has usually a yellowish abdomen, with one or two blackish bands, but in some cases the whole abdomen is black, except a small patch on the base and another at the tip. The male Bee has generally the abdomen coloured like the first-mentioned example of the worker, but sometimes it is wholly black, and in many cases it is black except the tip, which is dun. Indeed, these insects are so extremely variable, that the only method of determining their true arrangement is by taking a great number of nests, breeding the inmates, and subjecting them not only to careful external examination, but also to dissection of their internal anatomy.

The specific title "muscorum," i. e. " of the mosses," which is given to this Bee, is due to the material of which the nest is usually made. It was generally thought to be made exclusively of moss, but is in fact constructed of various substances, according to the locality. Mr. F. Smith mentions several instances where the Bees had made use of very singular and unexpected materials.

In one case, Bees were seen flying into a stable through the latticed window, collecting the little hairs that had fallen from the horses during the process of currying, making them up into bundles, and flying off with them. On being watched carefully, one of the Bees was seen to alight on some grass, not very far from the stable, and among the grass was found the nest, which